So today I reached up and turned on the rear heat. Immediately there was a loud, repetitive clicking/banging noise from the rear. Switched the air flow button (floor/roof) and the noise changed to a low thumping, not as loud as the other way. No matter which way the air flow setting was, the air came from the ceiling vents.

Thoughts as to what to look for? It worked fine last week, not not sure what changed...

 

Broken blend door actuator. There are two back there, one for temp and one for air flow location. Yours is the easier of the two to fix, it is located just under the change tray in the passenger side rear quarter panel molding. See my gallery for pictures or search for rear blend door.

 

Perfect, thanks for the info! Will check it out.

Chris

 

Chris here's a pic of what's under the quarter panel for the rear A/C system... The actuator circled in green is the one that controls air flow to the top or bottom vents (Motorcraft YH-1743). The one circled in red controls temperature (Motorcraft YH-1749). Both are prone to failures. I replaced the vent control actuator and unplugged the temperature control actuator since it defaults to the cold air position. I just control overall cabin temp from the front dash, works great here in Florida.
You can buy the actuators online at Rock Auto for about $40 each. The one circled in green you can access by removing the cup holder. The one circled in red requires removal of the quarter panel trim. But you can unplug it through the top tray piece once the tray is removed.



-Mike



Expedition rear A/C system. Green circled is vent controller, red circled is Temp control....

 

Mike! That is awesome! I am going to dig in to this later today.

Mucho Gracias!

Chris

 

I think in my gallery I used green for the temp one and red for the floor to ceiling. Shouldn't effect your repair!

 

FYI, popped the new part in yesterday and all is well again. Thanks to everyone for posting on this topic!
Chris